Portable self-locking clamp



June 6, 1950 co N 2,510,077

PORTABLE SELF-LOCKING CLAMP Filed Aug. 21, 1945 FIGURE l.

FIGURE 3.

FIGURE 4.

12 INVENTOR:

FA LPH K. CDFFMAA/ PER ATTORNEY Patented June 6,. 1950 The object ofthe invention ls to n-revise a --clamp particularly adapted to light work and set inclamping position bvmre pressurefrom the hands of theoperator when it will automatically retain such 's" ranium; to provide a device'of the kind indiatedin which the pressure "to be attained, whether-it be great' orslight,

can be determined by the proper selection of the members of which the slide connecting the jaws is composed; and to provide a clamp which is of simple construction by reason of consisting of few parts and which is, therefore, susceptible of cheap manufacture.

With this object in view the invention consists of a construction and combination of parts of which preferred embodiments are illustrated in the accompanying drawings in which- Figure 1 is a perspective view of one form of the invention;

Figure 2 is a vertical sectional view of the structure of Figure 1 in the plane of the axes of the members composing the slide;

Figure 3 is a perspective view similar to Figure 1 but showing a modification in which both jaws are movable with respect to the slide; and

Figure 4 is an elevational view of the invention in operative position with a work piece engaged by the jaws.

The jaws l and II are complemental and relatively movable, but one only is movable with respect to the slide I2 in that form of the invention shown in Figure 1, while both are adjustable along the slide when the invention follows the construction illustrated in Figure 3.

The slide is composed of the members or rods I2a, l2b and 120 arranged in parallelism and spaced a distance at least equal to the diameter of the members. If the invention be constructed as disclosed in Figures 1, 2 and. 4, the members In etc. are terminally fixed in sockets opening on the inner face of the jaw ll, thus fixing the position of that jaw with respect to the slide. The jaw l0, however, must be movable along the slide and it is, therefore, provided with body holes for the members of the slide, the holes extending through the jaw from the inner face.

Since the locking function of the movable jaw is accomplished by firm frictional engagement with the members of the slide, it is necessary to fiex the latter in the clamping operation. The jaws normally, therefore, are positioned at acute angles to the slide and are so arranged that their inner faces lie in converging planes, the noses or work engaging ends occupying the closest posi- 'ti'ons relatively a'n'd being provi-ded"with- :yield ing grip '-m"ats i t to: prevent 'marring theengaged workpiece.

In the use of the clamp the work pieice forexample,the blocks'l fi and 'Hi to which glue has -been"-"applied is' interposed between the :jaws

and they are brought 'int'o clamping' position by the "application of hand :-pressure at -'the heel ends. As the jaws are the moved into parallelism, the intervening portion of the slide is flexed, the slide members being bowed, as illustrated in Figure 4. This bowing of the members of the slide disaligns their axes and the axes of the holes in the movable jaw with the result that the said jaw is frictionally retained in its clamping position.

At the free end in the construction shown in Figure 1 and at either end in the construction shown in Figure 3, the slide is provided with-a bridging element l3. This element has the same angular position relative to the slide that the adjacent jaw occupies. The bridging element acts not only as a stop to prevent accidental removal of the jaw from the slide but it retains the members thereof in their parallel relation. But bowing of the slide can not be effected successfully to secure the movable jaw in clamping position if the bridging element be fixed to all the slide members. It is, therefore, fixed to only one, the center member IZb, in a socket of the element, the ends of the other members sliding in properly spaced similar sockets therein. By reason of this construction the bowing of the slide members is possible without destroying their uniformity of spacing.

While the use of the construction shown in Figure 3 requires the duplication of the bridging element, a certain advantage inures to that construction in that with it the clamping operation can be effected at varied points along the slide thus making more remote the time when the slide members will become permanently flexed by continued use and require renewal or reversal by rotating them one hundred eighty degrees from their original positions relative to each other and the jaws.

The pressure to be attained with the clamp determines the cross-sectional area of the members of which the slide is composed, the greater the cross-section the greater the pressure possible.

The invention having been described, what is claimed as new and useful is:

1. A clamp comprising co-operating jaws normally disposed with their complemental faces in converging planes, and a slide on which the jaws are mounted and including a plurality of spaced resilient rods arranged in parallelism, at least one of the jaws having body holes through which the rods pass, the relative diameters of the rods and holes being such that the jaw may move freely along the rods when the latter are straight but will frictionally bind on the same when both jaws are forced into parallel clamping engagement with an interposed work piece and the rods are flexed in consequence.

2. A clamp comprising co-operating jaws normally disposed with their complemental faces in converging planes, a slide on which the jaws are mounted and including a plurality of spaced resilient rods arranged in parallelism, at least one of the jaws having body holes through which the rods pass, the relative diameters of the rods and holes being such that the jaw may move freely along the rods when the latter are straight but will frictionally bind on the same when both jaws are forced into parallel clamping engagement with an interposed work piece and the rods are flexed in consequence, and a bridging member spanning the rods at their extremities and fixed with respect to at least one but slidable with respect to the others.

3. A clamp comprising co-operating jaws, and

a resilient slide on which the jaws are mounted, at least one of the jaws having a guide axially aligned with and affording a running engagement with the slide, the jaws being normally disposed in converging planes, so that when spread into parallelism for engagement with an interposed work piece, the guide and slide are disaligned thereby binding the sliding jaw and flexing the slide.

RALPH K. COFFlVIAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 923,805 Blake June 8, 1909 1,403,825 Wilkinson Jan. 17, 1922 1,567,210 Trester Dec. 29, 1925 1,659,342 Wetzler Feb. 14, 1928 2,340,316 Fest Feb. 1, 1944 2,407,436 Miller Sept. 10, 1946 FOREIGN PATENTS Number Country Date 6,493 Denmark Apr. 8, 1904 

